An immunocytochemical mapping of somatostatin in the cat auditory cortex

Using an indirect immunoperoxidase technique, the localization of somatostatin-28 (1-12)-like immunoreactive fibers and cell bodies in the auditory cortex of the cat (anterior, primary, secondary, temporal, ventral, ventroposterior, posterior and dorsoposterior auditory fields) was studied. In general, the distribution of SOM-ir structures is widespread in the auditory cortex of the feline. A high density of immunoreactive fibers as well as a low density of cell bodies containing somatostatin were observed in all the layers of the eight above-mentioned auditory fields. These data indicate that somatostatin-28 (1-12) could act as a neurotransmitter and/or a neuromodulator in the auditory cortex of the cat. The origin of the SOM-ir fibers in the auditory cortex of the cat, as well as the issue of whether the cell bodies containing somatostatin-28 (1-12) are local or projecting neurons is discussed.

Nicotinamide induces both proliferation and differentiation of embryonic stem cells into insulin-producing cells

In contrast to the consistent observation that methods that promote proliferation also dedifferentiate insulin-producing cells, useful in vitro differentiation protocols must drive both proliferation and differentiation. We herein describe an strategy in which the combination of nutrient restriction and nicotinamide supplementation results in a consistent increase in the mass of insulin-producing cells.

Is there a role for (99m)Tc-anti-CEA monoclonal antibody imaging in the diagnosis of recurrent colorectal carcinoma?

AIM

To evaluate the usefulness of immunoscintigraphy with an anti-CEA monoclonal antibody fragment labelled with (99m)Tc for early detection of colorectal recurrence in patients with rising serum CEA levels.

METHODS

Fifty-one consecutive patients (27 women, 24 men) with colorectal cancer (mean age 68.9+/-10.2 years) and rising CEA levels (16.2+/-18.2 ng/ml) were prospectively studied. Two immunoscintigraphy studies were performed in 8 patients (n=59). Immunoscintigraphy was performed after i.v. injection of 925 MBq of anti-CEA monoclonal antibody. Planar images of the thorax, abdomen and pelvis, as well as SPECT of the abdomen and pelvis were obtained at 4 and 24 hours after injection. In all cases an abdominal CT scan was previously performed. Findings were validated by histopathological analysis (28 cases) or by imaging and clinical follow-up of at least 6 months following the immunoscintigraphy (31 cases).

RESULTS

Forty-one patients did not show recurrence during follow-up. We found 18 cases with confirmed diagnosis of extrahepatic abdominal or pelvic diseases, 11 cases with liver metastases, 9 in the thorax and 2 in the bone. In patients with pelvic and extrahepatic abdominal disease, immunoscintigraphy was positive in 18 cases (14 true positive, 4 false positive). From the 14 true positive only 7 cases had been detected by CT. Immunoscintigraphy was negative in the remaining 41 cases (37 true negative, 4 false negative). Therefore, the sensitivity and specificity for immunoscintigraphy in extrahepatic abdominal and pelvic disease were 78% and 90%, respectively. CT results showed a lower sensitivity of 61% (p<0.05) and specificity of 83%. Liver metastases were detected by CT in 9 cases, but only 2 of these were identified using immunoscintigraphy.

CONCLUSION

Scintigraphy with anti-CEA monoclonal antibody fragment labelled with (99m)Tc is superior to CT for the detection of pelvic and extrahepatic abdominal recurrence of colorectal cancer, while CT is more sensitive in the detection of liver and lung metastases. Immunoscintigraphy has a limited usefulness in the detection of distant metastases, but it may be helpful in the diagnosis of suspected colorectal recurrence in patients with non-conclusive CT findings, when FDG-PET is not available.

Tetrofosmin as predictors of tumour response

Non-invasive imaging methods in the evaluation of chemotherapy response in malignant tumours are currently being explored. Standard Nuclear Medicine procedures seem to offer the clinician a promising tool in the management of those oncologic patients, who might benefit from chemotherapy. Early studies focused on the relationship between radionuclides used in tumour diagnosis and factors associated with multidrug resistance (MDR). The tumour expression of P-glycoprotein (Pgp) and multidrug resistance-related protein-1 expression (MRP) have been suggested as important factors in the failure of chemotherapy. Most studies found an association between Pgp levels and (99m)Tc-sestamibi ((99m)Tc-MIBI) or (99m)Tc-Tetrofosmin uptake ((99m)Tc-TF). Currently investigations in nuclear medicine oncology are focusing on the potential role of radionuclide imaging in the assessment of chemotherapy. Recent papers discuss the usefulness of radionuclides as (99m)Tc-MIBI and (99m)Tc-TF as non-invasive procedures to predict and to monitor therapy response in patients affected by malignant tumours treatable using chemotherapy. This chapter will review the latest development in (99m)Tc-TF, giving an overview of recent investigations carried out using this radiotracer in therapy oncology, with emphasis on its potential role as predictor of tumour response.

[Diagnosis of recurrent secondary hyperparathyroidism using double-phase 99m-Tc-MIBI gammagraphy after total parathyroidectomy with autotransplantation]

We present two cases of uremic patients with poor medical control of their secondary hyperparathyroidism. They had to undergo surgery to control symptoms. A total parathyroidectomy with autotransplant in the forearm muscles was performed. After a symptom-free period, both showed a recurrence of their hyperparathyroidism. A double phase 99mTc-MIBI scintigraphy was essential in order to correctly locate hypertrophic parathyroid gland. In one case there was a cervical recurrence and in the second patient hyperplasia in a forearm gland autotransplant was found. Both patients remained asymptomatic with medication during their follow up.

Charge transfer and dissociation in collisions of metal clusters with atoms

We present a combined theoretical and experimental study of charge transfer and dissociation in collisions of slow Li31(2+) clusters with Cs atoms. We provide a direct quantitative comparison between theory and experiment and show that good agreement is found only when the exact experimental time of flight and initial cluster temperature are taken into account in the theoretical modeling. We demonstrate the validity of the simple physical image that consists in explaining evaporation as resulting from a collisional energy deposit due to cluster electronic excitation during charge transfer.

[Fast method of labelling leukocytes with 99mTc HM PAO]

OBJECTIVE

To modify the method of labelling leukocytes with 99mTc HM-PAO by centrifuging 15 minutes at low gravity (g) instead of sedimentation at a variable time (30-90 minutes) to obtain leukocytic rich plasma (LRP).

METHODS

The g number recovering the greatest number of leukocytes was determined. The cellular composition of LRP obtained by centrifugation and sedimentation was analyzed. Lastly, labelling results in two groups of patients (p) were compared: one group of 118 p using the traditional sedimentation method (SM) and another of 124 p using the proposed centrifugation alternative (CM).

RESULTS

Centrifugation at 5xg produced the greatest recovery of leukocytes (93.1 5.1%). No significant difference was observed in leukocyte recovery in LRP obtained either by centrifugation or by sedimentation. However, red blood cell contamination was greater in centrifugation (12.8 4.9 x 108) than in sedimentation (7.7 3.5 x 108) (p < 0.0001). The comparison of the SM and the CM gave the following results:The number of leukocytes recovered in both methods was similar (73.9 15.1% vs 76.5 12.7%) with approximately the same platelet contamination (8.0 6.2 vs 8.4 6.5%). The number of red blood cell contaminants per leukocyte was 3.0 1.0 for the MS and 5.1 2.6 for the MC (p < 0.001). Labelling yield (LY) was somewhat higher for the CM (57.8 11.9%) than for the SM (50.8 12.6%) as a result of greater red blood cell contamination and superior radiochemical purity of the 99mTc HM-PAO used in the labelling by CM (90,9 5,9%) with regard to the SM (87.9 9.5%). No difference was observed in the scintigraphic images obtained with either of the methods, given the scarce uptake of the radiopharmaceutical by the red blood cells (3-7%) in comparison with the leukocyte uptake (70-90%).

CONCLUSION

The proposed MC considerably reduces the labelling time of leukocytes with 99mTc HM-PAO without affecting the quality of scintigraphic images and represents an important labelling alternative of great interest to the Radiopharmacy Units of Nuclear Medicine Services.

[Ghost cell detection in vitreous cytology: clinico-pathological correlation]

PURPOSE

To determine the prevalence of detection of ghost cells (GCs) in vitreous hemorrhages (VHs) and correlate it with the development of ghost cell glaucoma. To compare our results with those previously reported.

METHODS

Retrospective analysis of clinical records and vitreous cytology reports (cytospin and direct paraffin embedding) from patients undergoing vitrectomy for VH at Instituto Universitario de Oftalmobiología Aplicada and University Hospital, Valladolid, for the last 2 years.

RESULTS

76 VHs have been analysed; 45 corresponded to proliferative diabetic retinopathy and the remainder to several pathologies. GCs have been detected in 18 cases (25%) (4 out of 76 specimens were excluded): 14 were phakic and 4 pseudophakic. Most of 76 VHs lasted more than 2 months. No case of ghost cell glaucoma was detected, neither previously nor after vitrectomy.

CONCLUSIONS

The frequency of detection of GCs in vitreous cytology may vary according to the cytologic technique. In contrast with the information previously reported, ghost cell glaucoma is an unfrequent disease, particularly after vitrectomy, probably because of a better removal of hemorrhagic debris from the vitreous cavity nowadays. Nevertheless, this diagnosis should not be overlooked.

Theory, abstraction and design in medical informatics

OBJECTIVE

To analyze the scientific and engineering components of Medical Informatics. A clear characterization of these components should be undertaken to categorize different areas of Medical Informatics and create a research agenda for the future.

METHODS

We have adapted a classical ACM and IEEE report on computing to analyze Medical Informatics from three different viewpoints: Theory, Abstraction, and Design.

RESULTS

We suggest that Medical Informatics can be considered from these three perspectives: (1) Theory, from which medical informaticians formally characterize the properties of the objects of study, creating new theories or using and adapting existing theories (e.g., from mathematics), (2) Abstraction, from which medical informaticians deal with all aspects of medical information and create new abstractions, methods, and technology-independent models, which can be experimentally verified, and (3) Design, from which medical informaticians develop systems or act as information brokers or advisors between medical and technology professionals, to improve the quality of computer applications in medicine.

CONCLUSION

Based on this framework, we suggest that Medical Informatics has an independent scientific character, different from other applied informatics areas. Finally, we analyze these three perspectives using data mining in medicine.

[Distribution of hepatitis C virus genotypes among the hemodialysis population in the province of Alicante]

Hepatitis C virus (HCV) genotypes are irregularly distributed among the different geographic area and groups at risk.

OBJECTIVE

To study the different HCV genotypes and subtypes of hemodialyzed patients from Alicante.

METHODS

We studied 640 patients on haemodialysis (HD) and we determined the RNA-HCV and the genotypes in the 120 patients with antibodies against HCV (HCV-Ab). We compared the results with the genotypes of 1,370 patients from other groups at risk in the same geographic area.

RESULTS

RNA-HCV was not found in the serum in 15% (18/120) of the patients on HD who were HCV-Ab positive. Prevalence of the different genotypes in the 102 patients with positive viral RNA was the following: 1b: 56.8% (58/102), 1a: 19.6% (20/102), 3: 17% (17/102), 2a-2c: 1.9 (2/102), 2b: 0.9% (1/102) 4: 2.9 (3/102), 5: 0.9% (1/102). In conclusion, the genotype 1b was the most frequent in the patients studied in all these areas, and was the same as in the rest of the country. This genotype has been associated with the most severe hepatic disease and poor response to treatment, affecting the prognosis of these patients. The most frequent genotypes in HD in Alicante were 1b, 3 and 1a. HCV genotypes distribution among the HD units was not uniform in the different geographic areas. HCV genotypes distribution in the HD population is similar to other groups at risk from the same geographic area.

Quantified 99mTc-MIBI scintigraphy for predicting chemotherapy response in breast cancer patients: factors that influence the level of 99m Tc-MIBI uptake

The aim of this study was to establish whether tumour uptake of 99mTc-MIBI can predict response to chemotherapy in patients with breast carcinoma. Forty women suffering from breast carcinoma confirmed by tumour biopsy were studied prospectively. Fifteen patients subsequently underwent surgery and 25 were candidates for neoadjuvant chemotherapy. Breast scintigraphy was performed and planar and tomographic views (single photon emission computed tomography (SPECT)) were obtained after injection of 740 MBq of 99mTc-MIBI. The tumoural uptake was quantified by computer analysis. P-glycoprotein was evaluated by immunohistochemistry only in operable patients. The response to chemotherapy was evaluated at 3 months upon completion of treatment. The results of this study showed no relationship between 99mTc-MIBI uptake and the histological type or tumour size. There was an inverse correlation with the degree of tumour differentiation (P<0.05). 99mTc-MIBI uptake in negative P-glycoprotein lesions (2.36+/-1.72) was higher than in positive P-glycoprotein lesions (1.53+/-1.29), although the difference was not statistically significant. Lesions which responded to chemotherapy (16) showed higher 99mTc-MIBI uptake (7.70+/-5.20) than non-responding lesions (nine) (2.21+/-1.0) (P<0.001). In conclusion, there is a correlation between 99mTc-MIBI uptake in breast cancer and response to chemotherapy. Furthermore, 99mTc-MIBI uptake may be influenced by other factors such as the degree of tumour differentiation or tumour P-glycoprotein levels.

[Comparison of different techniques for cytologic analysis of vitreous specimens]

PURPOSE

To assess the efficacy of four methods to study the cytology of vitreous samples, and to evaluate the most efficient for routine analysis and immunocytochemical staining.

METHODS

Diluted and undiluted vitreous samples of 87 consecutive patients suffering vitreoretinal surgery for different diseases were analysed. The specimens were centrifugated and then processed through four different procedures: agar sandwich (29 cases), direct paraffin embedding (33 cases), cytospin preparations (82 cases) and cytoblock (8 cases).

RESULTS

Evaluable material was obtained in: agar sandwich 18 out of 29 cases (62%), direct paraffin embedding 32 out of 33 cases (96.9%), cytospin 72 out of 82 cases (87.8%) and cytoblock 1 out of 8 cases (12.5%).

CONCLUSIONS

Direct paraffin embedding and cytospin are the most efficient procedures for routine purposes. Agar sandwich technique seems to be useful for studying small pieces of tissue. Direct paraffin embedding and agar sandwich technique seems to be valuable for immunocytochemistry. After 8 cases processed with cytoblock, our experience did not show valuable results for processing vitreous samples.

Opposite effects of low and high doses of arginine on glutamate-induced nitric oxide formation in rat substantia nigra

L-arginine is a very versatile amino acid that is involved in many important physiological processes such as protein, nitric oxide (NO), agmatine, putrescine, urea, L-ornithine or creatine synthesis and is essential for posttranslational arginylation of protein. The present study was designed to evaluate in vivo the effect of L-arginine on NO production in substantia nigra. In vivo spectroscopic and voltammetric studies were addressed in rats to record modifications in methemoglobin and NO levels under glutamate stimulation. Results showed that, under physiological L-arginine extracellular concentration, the intranigral infusion of glutamate produced an increase in NO levels. When a low dose of L-arginine was co-infused with glutamate, a persistent and higher increase in NO levels was observed. The co-infusion of glutamate with a moderate dose of L-arginine induced drastic and persistent NO production. It was also observed that high doses of either L-arginine or D-arginine inhibit NO production. Subsequently, these data show that L-arginine and D-arginine are involved in a mechanism that inhibits NO production.

Soil pollution by oxidation of tailings from toxic spill of a pyrite mine

On the 25th April 1998, toxic water and tailings from a pyrite mine of Aznalcóllar (southern Spain) spilled into the Agrio and Guadiamar River Basin affecting some 40 km2. In five sectors throughout the basin, we monitored the physical and chemical properties of the tailings as well as the degree of pollution in the soils on four different sampling dates: 5 May, 20 May, 4 June and 22 July 1998. The characteristics of the tailings deposited on the soils are shown to be related to distance from the spill. The oxidation rate of the tailings and the solubilization of the pollutant elements were more pronounced in the middle and lower sectors of the basin, where the particle size was finer, the sulfur content higher and the bulk density less. The increases in water-soluble sulfates, Zn. Cd and Cu were very rapid (the highest values being reached 25 days after the spill) and intense (reaching 45% of the total Cu, 65% of the total Zn and Cd). Meanwhile, the increases in water-soluble As, Bi, Sb, Pb and Tl were far lower (ranging between 0.002% of the total Tl and 2.5% of the total As) and less rapid in the case of As, Bi and Pb (the highest values for these elements being reached 40 days after the spill). These soluble elements infiltrated the soils with the rainwater, swiftly augmenting the soil pollution. Twenty-five days after the spill, when the rainfall ranged between 45 and 63 mm, the first 10-cm of the soils in the middle and lower sectors of the basin exceeded the maximum concentration permitted for agricultural soils in Zn, Cu and Tl. At 40 days after the spill, when the rainfall ranged between 60 and 89 mm, all the soils reached or exceeded the maximum permitted concentrations for As and Tl. Nevertheless, the pollutants tended to concentrate in the first 10 cm of the soils without seriously contaminating either the subsoil or the groundwaters. Consequently, a rapid removal of the tailings and the ploughing of the first 25-30 cm of the soils would be urgent measures to diminish pollutant concentration in the soils affected by the spill.

[Efficacy of direct paraffin embedding in cytological analysis of vitreous from proliferative vitreo-retinopathy (PVR)]

PURPOSE

To assess the efficacy of direct paraffin embedding in cytological analysis of vitreous samples in patients suffering from PVR, against the commonly used method for this purpose (cytospin).

METHOD

Undiluted vitreous or vitreous fluids from 40 subsequent patients with PVR were collected and processed (samples collected from cassette at the end of aspiration line in final stage of vitrectomy process). 40 samples underwent cytospinning, 24 samples were paraffin embedded. Specimens were assessed by an expert ocular pathologist and tested samples were assigned to scoring and non scoring groups (where scoring means at least three cells per field in x60 magnification).

RESULTS

All 24 paraffin embedding samples scored according to criteria while 36 of 40 cytospinned samples complied with scoring criteria. Differences were not statistically significant. Macrophages (87.5%) and pigmented cells (85%) were the most frequent findings.

CONCLUSIONS

Direct paraffin embedding is useful for cytological studies in vitreous samples of PVR patients.

[Nosocomial transmission of the hepatitis C virus in hemodialysis: monitors, personnel, or both?]

BACKGROUND

The Hepatitis C virus (HCV) infection is the most frequent cause of hepatic disease in the dialysis population. Many observations suggest that nosocomial transmission is the principal way of infection.

OBJECTIVE

The aim of this study was to investigate HCV outbreak in a hemodialysis (HD) unit, using epidemiological and molecular methods.

METHODS

50 patients in a HD unit were tested for HCV-RNA by reverse transcription-polymerase chain reaction (PCR), and the hepatitis C genotype determination (reverse hybridization assay). We analyzed the distribution of different genotypes by shifts and dialysis machines and the temporal association in the appearance of the HCV cases.

RESULTS

21 of 50 patients (42%) showed detectable anti-HCV antibodies (HCV-Ab) in serum. The prevalence of HCV RNA positivity was 90.4% (19/21) among these patients. None of the HCV-Ab negative patients detectable HCV virus in thein blood. The PCR genotyping of HCV RNA was performed in 19 patients. It detected the presence of HCV subtype 1b in 10 out of 19 viremic patients (52.6%), HCV-subtype I a in 31.5% of the patients (6/19) and genotype 3 in 15.7% (3/19) of the viremic patients. All patients had been infected by only one genotype. We found epidemiological correlation and temporal association between the genotypes 1b (p < 0.05) and 3 (p < 0.05) with the shifts. The HCV genotype 1a shows statistical association with the machine 1 (p < 0.05) but not temporal association.

CONCLUSIONS

HCV genotype 1b was dominant in our cohort of HCV-infected patients. There was a high level of agreement between the PCR detection of HCV RNA and the detection of antibodies against the HCV genome. Genotyping and epidemiological analysis suggest that horizontal nosocomial patient to patient transmission plays an important role in the epidemiology of HCV in dialysis patients. There is a need for stringent implementation and regular auditi of infection control measures.